Conventionally, a navigation system employs a technique relating to a route learning; that is, upon deviating from an optimum route, an actual traveling route is stored as a learned section, and when searching is performed for an optimum route at a later time, in the case where a start point and an end point of the learned section are included in the route, the route from the start point to the endpoint is replaced by the learned section. Patent document 1 describes a technique regarding such navigation system as described above.
PRIOR ART DOCUMENT
Patent Document
    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-174280